Students participating in the annual Entrepreneurship Expo at Vista Magnet Middle School this week were taught to promote their products, and it was clear that some young merchants had taken the lesson to heart.

“We got duct-tape ties!” student Heather Miller cried out to passing shoppers at the event, held Wednesday in the school’s gym. “Three dollars! We’re the only place that has duct-tape ties! One thing about these is, you can wear them underwater!”

Heather and her companions further informed shoppers that another booth was selling duct-tape purses for $7, a price they could easily beat.

The expo, which started six years ago as a math exercise for students, has grown into a lively annual marketplace. It attracted more than 1,000 shoppers over two hours on Wednesday afternoon.

Teacher Jennifer Eckle said the first expo, in 2006, consisted of 10 tables. This year, 59 tables were manned by 1,500 students — about 25 percent of the school’s population.

The exercise required participating students to create a product — about half the items were baked goods or other foods — and sell them at the market. In a new twist this year, students met with teachers a few weeks ago for a “quality control” session in which they got tips on how to improve and promote their merchandise during the expo.

“This is the first time we included a marketing component,” Principal Jose Villarreal said. “Signs. Samples. Going out and encouraging customers to come to their booth and pitch their product.”

And that they did. The gym was a cacophony of sales pitches that echoed through a room filled with scents of cotton candy and other sweets from various booths.

Eighth-grader McKennah Edmunds took the exercise one step further by forming her own company, McCookie, which she presides over as president and CEO.

“It takes a lot of work to make a lot of cookies,” she said about what she learned from the experience. “You have to have a whole business perspective. It takes a lot of people skills.”

McKennah took in more than $70 at the expo by selling cookies for $1 and cookie sandwiches for $2.

“I’ll probably never eat another cookie again,” she said.

Eighth-grader Karla Perez peddled tamarind apples, which she made at home with her mother.

“They were originally $3, but they were selling too slowly,” she said.”

Karla dropped the price to $2 and sold about seven, but toward the end of the expo she still had several left.

Eckle stopped by the booth and offered her $1 for an apple. She wasn’t just being a savvy consumer — students this year were taught to adjust prices according to market, so bartering was part of the day’s lessons.

Some students attracted costumers by hawking or with eye-catching signs. Student Iesha Carter lured people to her table by wearing a small decal of an eye on the end of her nose. When people stopped to ask what it was, she pitched the bookmarks she was selling.